Bring in support for netmap, a framework for very efficient packet

I/O from userspace, capable of line rate at 10G, see

	http://info.iet.unipi.it/~luigi/netmap/

At this time I am bringing in only the generic code (sys/dev/netmap/
plus two headers under sys/net/), and some sample applications in
tools/tools/netmap. There is also a manpage in share/man/man4 [1]

In order to make use of the framework you need to build a kernel
with "device netmap", and patch individual drivers with the code
that you can find in

	sys/dev/netmap/head.diff

The file will go away as the relevant pieces are committed to
the various device drivers, which should happen in a few days
after talking to the driver maintainers.

Netmap support is available at the moment for Intel 10G and 1G
cards (ixgbe, em/lem/igb), and for the Realtek 1G card ("re").
I have partial patches for "bge" and am starting to work on "cxgbe".
Hopefully changes are trivial enough so interested third parties
can submit their patches. Interested people can contact me
for advice on how to add netmap support to specific devices.

CREDITS:
    Netmap has been developed by Luigi Rizzo and other collaborators
    at the Universita` di Pisa, and supported by EU project CHANGE
    (http://www.change-project.eu/)
    The code is distributed under a BSD Copyright.

[1] In my opinion is a bad idea to have all manpage in one directory.
  We should place kernel documentation in the same dir that contains
  the code, which would make it much simpler to keep doc and code
  in sync, reduce the clutter in share/man/ and incidentally is
  the policy used for all of userspace code.
  Makefiles and doc tools can be trivially adjusted to find the
  manpages in the relevant subdirs.

1 files changed, 98 insertions, 0 deletions

diff --git a/sys/net/netmap_user.h b/sys/net/netmap_user.h
new file mode 100644
index 0000000..c9443b8
--- /dev/null
+++ b/sys/net/netmap_user.h
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ * 
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the
+ *      distribution.
+ * 
+ *   3. Neither the name of the authors nor the names of their contributors
+ *      may be used to endorse or promote products derived from this
+ *      software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY MATTEO LANDI AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTEO LANDI OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * $FreeBSD$
+ * $Id: netmap_user.h 9495 2011-10-18 15:28:23Z luigi $
+ *
+ * This header contains the macros used to manipulate netmap structures
+ * and packets in userspace. See netmap(4) for more information.
+ *
+ * The address of the struct netmap_if, say nifp, is determined
+ * by the value returned from ioctl(.., NIOCREG, ...) and the mmap
+ * region:
+ *	ioctl(fd, NIOCREG, &req);
+ *	mem = mmap(0, ... );
+ *	nifp = NETMAP_IF(mem, req.nr_nifp);
+ *		(so simple, we could just do it manually)
+ *
+ * From there:
+ *	struct netmap_ring *NETMAP_TXRING(nifp, index)
+ *	struct netmap_ring *NETMAP_RXRING(nifp, index)
+ *		we can access ring->nr_cur, ring->nr_avail, ring->nr_flags
+ *
+ *	ring->slot[i] gives us the i-th slot (we can access
+ *		directly plen, flags, bufindex)
+ *
+ *	char *buf = NETMAP_BUF(ring, index) returns a pointer to
+ *		the i-th buffer
+ *
+ * Since rings are circular, we have macros to compute the next index
+ *	i = NETMAP_RING_NEXT(ring, i);
+ */
+
+#ifndef _NET_NETMAP_USER_H_
+#define _NET_NETMAP_USER_H_
+
+#define NETMAP_IF(b, o)	(struct netmap_if *)((char *)(b) + (o))
+
+#define NETMAP_TXRING(nifp, index)			\
+	((struct netmap_ring *)((char *)(nifp) +	\
+		(nifp)->ring_ofs[index] ) )
+
+#define NETMAP_RXRING(nifp, index)			\
+	((struct netmap_ring *)((char *)(nifp) +	\
+	    (nifp)->ring_ofs[index + (nifp)->ni_num_queues+1] ) )
+
+#if NETMAP_BUF_SIZE != 2048
+#error cannot handle odd size
+#define NETMAP_BUF(ring, index)				\
+	((char *)(ring) + (ring)->buf_ofs + ((index)*NETMAP_BUF_SIZE))
+#else
+#define NETMAP_BUF(ring, index)				\
+	((char *)(ring) + (ring)->buf_ofs + ((index)<<11))
+#endif
+
+#define	NETMAP_RING_NEXT(r, i)				\
+	((i)+1 == (r)->num_slots ? 0 : (i) + 1 )
+
+/*
+ * Return 1 if the given tx ring is empty.
+ *
+ * @r netmap_ring descriptor pointer.
+ * Special case, a negative value in hwavail indicates that the
+ * transmit queue is idle.
+ * XXX revise
+ */
+#define NETMAP_TX_RING_EMPTY(r)	((r)->avail >= (r)->num_slots - 1)
+
+#endif /* _NET_NETMAP_USER_H_ */